Absorption stopped-flow and light-scattering stopped-flow, flow-flash, and dye-laser photolysis devices have been interfaced to a Super-Nova computer with 20K of core memory which provides on-line data acquisition and sophisticated statistical analysis of the kinetic data. Experiments probing the mechanism of ligand-binding in diverse pure hemoglobins are in progress. In most instances, purification is by isoelectric focussing in gels. We have been particularly active in conducting oxygen-pulse experiments on the dimeric co-operative hemoglobins of several invertebrates. The differential equations arising from various models are solved numerically and the results compared with experiment. We are particularly interested in elucidating the mechanism by which the globin moiety modifies the reactivity of the heme iron in the protein. Detailed kinetic studies are nearing completion on the minor human hemoglobins and are in progress on the co-operative and non-co-operative dimeric hemoglobins and myoglobins from numerous invertebrates under varying conditions of pH, temperature, ligand and protein concentrations.